Econoline E350 1 Ton V8-5.4L Prop SOHC VIN Z (1998)
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The pinion gear depth is correct. Decrease the differential ring gear backlash.
Tire Wear Patterns & Frequency Calculations
Wheel and tire NVH concerns are directly related to vehicle speed and are not generally affected by acceleration, coasting or decelerating. Also,
out-of-balance wheel and tires can vibrate at more than one speed. A vibration that is affected by the engine rpm or is eliminated by placing the
transmission in NEUTRAL is not related to the tire and wheel. As a general rule, tire and wheel vibrations felt in the steering wheel are related to the
front tire and wheel assemblies. Vibrations felt in the seat or floor are related to the rear tire and wheel assemblies. This can initially isolate a concern to
the front or rear.
Careful attention must be paid to the tire and wheels. There are several symptoms that can~be caused by damaged or worn tire and wheels. Carry out a
careful visual inspection of the tires and wheel assemblies. Spin the tires slowly and watch for signs of lateral or radial runout. Refer to the tire wear chart
to determine the tire wear conditions and actions.
For a vibration concern, use the vehicle speed to determine tire/wheel frequency and rpm. Calculate tire and wheel rpm and frequency by carrying out
and following:
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Measure the diameter of the tire.
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Record the speed at which the vibration occurs. Obtain the corresponding tire and wheel rpm and frequency from the Tire Speed and Frequency
Chart.
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If the vehicle speed is not listed, divide the vehicle speed at which the vibration occurs by 16 (km/h (10 mph). Multiply that number by 16 km/h
(10 mph) tire rpm listed for that tire diameter in the chart. Then divide that number by 60. For example: a 40 mph vibration with 835 mm (33 in)
tires. 40 divided by 10 = 4. Multiply 4 by 105 = 420 rpm. Divide 420 rpm by 60 seconds = 7 Hz at 40mph.
